Different people different thoughts, different sites and niches different techniques. Stumbles can help if you will have something very interesting. I have tried stumbles once but I haven't something on the sites which users can gain or which can urge them to read or whatever(it was a site about my services).
Some people fond of having links, I shall say that is not bad but it can be very very harmful if you are going to have thousands links on the sites which are not related to your site. I don't think, i am sure that will harm your site so don't do it to your site.
Regarding content, everyone focus on the keywords, phrases and other stuff. Keyword density and having good proportion of keywords is good but what if you have only keywords and nothing else so don't use your keywords 100 times in a 500 words article.
I shall suggest work consistently on your site to have good positions in SERPS and attaining a good
PR.